JP3342221B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine and a laser beam printer, and more particularly, to a method for transferring a toner image formed on an image carrier onto a transfer material carried by the transfer material carrier. The present invention relates to an image forming apparatus for transferring.

[0002]

2. Description of the Related Art Hitherto, as a color image forming apparatus such as a copying machine and a laser beam printer, a multi-transfer type using a hollow transfer drum is well known. In general, a hollow transfer drum (transfer material carrier) is formed by forming a dielectric sheet into a cylindrical shape, and the transfer material is adsorbed onto the transfer drum, and the respective colors are sequentially colored from the back of the dielectric sheet using a corona charger. The transfer is performed. On the other hand, in the same multiple transfer system, the applicant has proposed a multiple transfer system in which a dielectric sheet is supported on a rigid support as shown in FIG.

In FIG. 6, a cylindrical electrophotographic photosensitive member (hereinafter, referred to as a “photosensitive drum”) 103 as an image carrier is rotationally driven in the direction of an arrow (counterclockwise), and uniformly by a charging unit 110. It is charged and then irradiated with a light image by a laser exposure device 111 or the like to form an electrostatic latent image on the surface. This electrostatic latent image is developed by a developing unit 101a that contains a color developer such as yellow (Y), magenta (M), cyan (C), or black (Bk), which is carried on a rotatable support. , 101b, 101c, and 101d, the toner is attached and visualized to form a toner image.

On the other hand, the transfer material 107 is conveyed by being fixed by a gripper 105 to the surface of a transfer drum (transfer material carrier) 102 in the form of a drum, for example, and is electrostatically adsorbed by an adsorption device 108 to be transferred onto the transfer drum 102. Is held.
The toner image on the photosensitive drum 103 is transferred to a transfer device, that is, a transfer drum 102 (hereinafter, referred to as a transfer drum 102) in which an elastic layer 122 and a dielectric layer 123 are provided on an aluminum core 121 as shown in FIG. The image is superimposed and transferred onto a transfer material 107 wound around a “solid transfer drum”. Such a solid transfer drum system has the advantage that the mechanical strength is superior and the structure can be simplified as compared with the conventional hollow transfer drum system.

A further explanation will be given with reference to FIG. First, the electrostatic latent image formed on the photosensitive drum 103 by exposure based on the image signal of the first color is converted into, for example, a yellow (Y) developing device 1.
After being visualized by 01a, the image is transferred to a transfer material 107 held on a transfer drum 102. Subsequently, after the residual toner on the photosensitive drum 103 is cleaned by the cleaner 112, an electrostatic latent image of the second color is formed on the photosensitive drum 103 by exposure based on the image signal of the second color. After being visualized by the developing device 101b, the image is superimposed and transferred onto the transfer material 107 on the transfer drum 102 on which the first color yellow toner image is transferred. Next, the same method as described above is repeated to transfer, for example, cyan (C) as the third color and black (Bk) as the fourth color onto the transfer material 107 on the transfer drum 102, respectively. Thereafter, the transfer material 107 is neutralized by the separation neutralization device 106, separated from the transfer drum 102 by the separation claws 114, and fixed by the fixing device 104 to obtain a permanent image.

The transfer drum 102 after the transfer material 107 is separated
The toner adhered to the surface of the dielectric layer 123 is removed by the transfer member cleaner 113, and the dielectric layer 123 is removed by the static eliminator 109.
The residual charges on the surface are eliminated and electrically initialized.

In the color image forming apparatus performing the multiple transfer as described above, the static elimination is controlled at a constant voltage so that the static elimination voltage (alternating electric field) _Vpp is constant regardless of the environment.

[0008]

[0007] However, if a neutralizing voltage V _pp and a constant voltage control in the above-mentioned solid transfer drum system, V so as to satisfy the neutralization properties in low-temperature and low-humidity environment _pp
In the high temperature and high humidity environment, there is an inconvenience that poor suction may occur after the paper has passed through the durable sheet or the transfer property may be changed. This is because the resistance of the dielectric layer 123 is reduced in a high-temperature and high-humidity environment,
In addition, the discharge starting voltage decreases because the capacity increases,
Since V _pp does not change, an excessive discharge occurs, and paper powder or scattered toner fuses to the dielectric layer 123 and the dielectric layer 1
23 was found to be caused by lowering the surface resistance. For this reason, the charge on the surface of the dielectric layer 123 for adsorbing the transfer material 107 escapes to cause poor adsorption. Further, the dielectric layer 123 is contaminated, and the resistance and the like change, so that the transferability changes.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus which ensures sufficient charge elimination of a transfer material carrier and prevents contamination of the transfer material carrier even when the environment changes. It is intended for.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and comprises a rotatable transfer material carrier having a dielectric layer and a transfer electrode, and a rotatable transfer material carrier disposed in contact with the dielectric layer. Having an image carrier on which a toner image is formed on the surface, adsorbing a transfer material to the dielectric layer, and applying a transfer voltage to a transfer electrode on the back side of the dielectric layer, In an image forming apparatus for electrostatically transferring a toner image on an image carrier to a transfer material on the dielectric layer, an alternating voltage is applied between the transfer material carrier and the transfer material after the transfer material is separated, thereby forming the dielectric material. A static elimination member for removing the residual charge on the surface of the body layer, a temperature and humidity detecting means for detecting the temperature and humidity of the atmosphere, and a peak-to-peak voltage of an alternating voltage applied between the transfer material carrier and the static elimination member, Control to change according to the detection result of the temperature and humidity detecting means Characterized in that it comprises a stage.

[0011]

The hardness of the charge removing member is determined by Asker C
It is preferable to set the angle between 10 ° and 60 ° in the measurement.

[0013]

[Function] Based on the above configuration, depending on the temperature and humidity of the atmosphere,
The resistance value of the dielectric layer changes. Therefore, the peak-to-peak voltage of the alternating voltage applied to the neutralizing member is changed based on the temperature and humidity detected by the temperature and humidity detecting means. By doing so, even when the resistance value of the derivative layer changes, good static elimination can be performed.

It is more preferable that the static elimination is controlled by a constant current.

Further, it is more preferable that the hardness of the neutralizing member is 10 ° or more and 60 ° or less as measured by Asker C.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. <Embodiment 1> FIG. 1 shows a schematic configuration of a main part of an image forming apparatus according to the present invention, and FIG. 2 shows a schematic configuration of the whole. The image forming apparatus of the present embodiment is a color laser beam printer.

The configuration will be briefly described. A drum-shaped electrophotographic photosensitive member (hereinafter, referred to as a “photosensitive drum”) as an image carrier is rotationally driven in an arrow direction (clockwise), uniformly charged by a charging unit 10, and thereafter, the laser exposure device 1
1 irradiates a light image to form an electrostatic latent image on the surface. This electrostatic latent image is stored on a rotatable support.
Developing devices 1a, 1b containing yellow (Y)), magenta (M), cyan (C), black (Bk), and other developers (toners), respectively.
At 1c and 1d, toner is attached and visualized to form a toner image.

On the other hand, the transfer material 7 is conveyed by being fixed to the surface of a drum-shaped fixed transfer drum (transfer material carrier) 2 by a gripper 5, electrostatically attracted by a suction device 8, and is transferred onto the fixed transfer drum 2. Will be retained. The toner image on the photosensitive drum 3 is transferred onto the transfer material 7 wound around the solid transfer drum 2 in a superimposed manner. Thereafter, the transfer material 7 is neutralized by the separation and neutralization device 6, separated from the surface of the transfer drum 2 by the separation claws 14, and fixed by the fixing device 4 to obtain a permanent image.

After the transfer material 7 is separated from the transfer drum 2, the toner adhered to the surface of the transfer drum 2 is removed by a transfer member cleaner 13, and the charge is removed by a charge removing roller (charge removing member) 9 to be electrically initialized.

In the first embodiment, the temperature / humidity of the atmosphere is detected by a temperature / humidity sensor (temperature / humidity detecting means) 15, and according to the detection result, a static elimination power supply 17 is provided via a control circuit (control means) 16. , The peak-to-peak voltage V of the alternating voltage during static elimination
Change _pp .

In this embodiment, the photosensitive drum 3 has a negatively charged O
A PC having a charge transport layer (hereinafter referred to as “CT layer”) having a thickness of 25 μm provided on the charge generation layer was used. The transfer drum was a drum-shaped aluminum cored bar 2 as shown in FIG.
An elastic body 22 having a thickness of 5.5 mm and a volume resistance of 10 ⁵ Ω · cm or less is wound on
A sheet coated with a dielectric transfer sheet (dielectric layer) 23 having a value of 0 ¹⁴ to 10 ¹⁶ Ω · cm and a relative dielectric constant of 9 was used. In addition, an aluminum roller was used as the charge removing roller 9. At this time, the temperature and humidity were 15 ° C., 10%, 23 ° C., 60%,
FIG. 3 shows the results obtained by changing the peak-to-peak voltage (static elimination voltage) V _pp of the alternating voltage during static elimination in three environments of 30 ° C. and 80% and measuring the static elimination AC current at that time. Also,
FIGS. 7, 8, and 9 show the results of measuring the static elimination property and the contamination of the dielectric transfer sheet.

FIG. 2 shows that when the temperature and humidity of the atmosphere rise,
It can be seen that the static elimination AC current increases. 7, 8, and 9, the optimum static elimination voltage V _pp at 15 ° C. and 10% is 2.25 kV, and the optimal static elimination voltage V _pp at 23 ° C. and 60% is 1.75 kV and 30 ° C. , optimal neutralization voltage V _pp at 80% is 1.25 kV, it can be seen that the optimal neutralization voltage V _pp by the temperature and humidity of the atmosphere is different. Therefore, the temperature and humidity of the atmosphere are detected by the temperature and humidity sensor 15, and the static elimination voltage V _pp is changed according to the detection result, thereby satisfying the static elimination property in all environments and preventing the dielectric transfer sheet 23 from being contaminated. be able to. <Embodiment 2> FIG. 4 shows a main part of an image forming apparatus according to Embodiment 2. The same members and the same functions as in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In this embodiment, the static elimination power supply 18 is applied to the static elimination roller 9 with a constant static elimination AC current.

In this embodiment, the photosensitive drum 3 has a negatively charged O
A PC having a CT layer having a thickness of 25 μm provided on a charge generation layer is used. The transfer drum is an elastic body having a thickness of 5.5 mm and a volume resistance of 10 ⁵ Ω · cm or less on an aluminum core 21. 2
2 with a thickness of 75 μm and a volume resistance of 10 ¹⁴ to 1
A sheet coated with a dielectric transfer sheet 23 having 0 ¹⁶ Ω · cm and a relative dielectric constant of 9 was used. In addition, an aluminum roller was used as the charge removing roller. At this time, temperature and humidity 15 ° C, 10%
FIG. 11 shows the results obtained by varying the AC current value of static elimination in three environments of 23 ° C., 60%, 30 ° C., and 80%, and measuring the static elimination property and the contamination of the dielectric transfer sheet 23.
This is shown in FIGS.

Thus, the static elimination is performed with an AC constant current, and in this embodiment, by setting the current value to 1100 μA, the static elimination property can be satisfied in all environments and the contamination of the dielectric transfer sheet 23 can be prevented. did it. Further, by performing the AC constant current, it is not necessary to check information on the atmosphere using a temperature / humidity sensor, so that the apparatus can be simplified and the cost can be reduced. Furthermore, even if the resistance and capacity of the dielectric transfer sheet 23 or the resistance of the charge removing roller 9 vary, an appropriate bias can be applied, and the latitude can be widened. <Embodiment 3> In this embodiment, the hardness of the charge eliminating roller 9 is set to 10 ° or more and 60 ° or less by Asker C measurement.

In this embodiment, the photosensitive drum 3 has a negatively charged O
A PC having a CT layer having a thickness of 25 μm provided on a charge generation layer is used. The transfer drum is an elastic body having a thickness of 5.5 mm and a volume resistance of 10 ⁵ Ω · cm or less on an aluminum core 21. 2
2 with a thickness of 75 μm and a volume resistance of 10 ¹⁴ to 1
A sheet coated with a dielectric transfer sheet 23 having 0 ¹⁶ Ω · cm and a relative dielectric constant of 9 was used. Here, the static elimination roller 9 is changed in hardness from 5 ° to 100 ° (Asker C measurement),
FIG. 13 shows the results of measuring the contamination of the dielectric transfer sheet 23 under an environment of 80%. Here, hardness from 5 ° to 8
Rollers up to 0 ° use EPDM rollers and have a hardness of 100
A roller made of aluminum was used for the roller of °.

FIG. 13 shows that the hardness of the charge eliminating roller 9 is 60 °.
In the following, it can be seen that the latitude has spread for the contamination of the transfer drum. This is because the vibration caused by the application of AC at the time of static elimination is absorbed by lowering the hardness of the neutralizing roller 9 and the energy applied to the dielectric transfer sheet 23 is reduced, so that the fusion hardly occurs. However, since the hardness of the roller with a hardness of 5 ° is very small, the pressure balance between the left and right is very severe, and the nip width between the right and left changes even with a slight difference in pressure. The adverse effect that the transferability changes between the left and right sides has occurred.

Thus, by setting the hardness of the charge eliminating roller 9 to 10 ° or more and 60 ° or less by Asker C measurement, the charge eliminating property can be satisfied, and the latitude against contamination of the dielectric transfer sheet 23 can be widened. Further, it is possible to reduce the static elimination noise.

[0029]

As described above, according to the present invention,
It has a means for detecting the temperature and humidity of the atmosphere, and by changing the peak-to-peak voltage (static elimination voltage) of the alternating voltage according to the detection result, achieves good static elimination even when the temperature and humidity change, and The transfer material carrier can be prevented from being contaminated. Further, it is more preferable that the static elimination be performed with an AC constant current. Further, the hardness of the static elimination member was set to 10 ° by Asker C measurement.
The angle should be at least 60 ° or less.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part of an image forming apparatus according to a first embodiment.

FIG. 2 is a schematic configuration diagram of the entire image forming apparatus according to the first embodiment.

FIG. 3 is a diagram illustrating a relationship between a static elimination voltage and a static elimination AC current.

FIG. 4 is a schematic configuration diagram of a main part of an image forming apparatus according to a second embodiment.

FIG. 5 is a schematic configuration diagram of a main part of a conventional image forming apparatus.

FIG. 6 is an overall schematic diagram of a conventional image forming apparatus.

FIG. 7 is a diagram showing the relationship between the static elimination voltage at 15 ° C. and 10%, the static elimination property, and the contamination of the transfer sheet in Example 1.

FIG. 8 is a diagram showing a relationship between a static elimination voltage at 23 ° C. and 60%, static elimination properties, and transfer sheet contamination in Example 1.

FIG. 9 is a diagram showing the relationship between the static elimination voltage at 30 ° C. and 80%, the static elimination property, and the contamination of the transfer sheet in Example 1.

FIG. 10 is a diagram showing a relationship between a static elimination voltage at 15 ° C. and 10%, a static elimination property, and contamination of a transfer sheet in Example 2.

FIG. 11 is a diagram showing a relationship between a static elimination voltage at 23 ° C. and 60%, static elimination properties, and transfer sheet contamination in Example 2.

FIG. 12 is a diagram showing a relationship between a static elimination voltage at 30 ° C. and 80%, static elimination properties, and transfer sheet contamination in Example 2.

FIG. 13 is a diagram illustrating a relationship between the hardness of a charge removing roller and a charge removing voltage in a third embodiment.

[Explanation of symbols]

 1a, 1b, 1c, 1d Developing device 2 Transfer material carrier (transfer drum) 3 Image carrier (photosensitive drum) 4 Fixing device 5 Gripper 6 Separation and static eliminator 7 Transfer material 8 Suction device 9 Static eliminator (Static roller) 10 Charging Means 11 Laser exposure device 12 Cleaner 13 Transfer member cleaner 14 Separation claw 15 Temperature / humidity detecting means (temperature / humidity sensor) 16 Controller (control circuit) 21 Core metal 22 Elastic body 23 Dielectric layer (dielectric transfer sheet)

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takao Kume 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Motoi Kato 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Toshihiko Ochiai 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Toshiaki Miyashiro 3-30-2, Shimomaruko 3-chome, Ota-ku, Tokyo Canon Inc. ( 56) References JP-A-7-28341 (JP, A) JP-A-7-28343 (JP, A) JP-A-6-250532 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , (DB name) G03G 15/16 G03G 15/00 303

Claims (2)

(57) [Claims] A rotatable transfer material carrier having a dielectric layer and a transfer electrode; and an image carrier having a surface on which a toner image is formed in contact with the dielectric layer. The toner image on the image carrier is electrostatically applied to the transfer material on the dielectric layer by applying a transfer voltage to the transfer electrode on the back side of the dielectric layer while adsorbing the transfer material on the body layer. An image forming apparatus for transferring a transfer material to the transfer material carrier, after removing a transfer material, applying an alternating voltage to remove a residual charge on the surface of the dielectric layer; and detecting temperature and humidity of the atmosphere. Temperature and humidity detecting means, and control means for changing a peak-to-peak voltage of an alternating voltage applied between the transfer material carrier and the charge removing member in accordance with a detection result of the temperature and humidity detecting means. An image forming apparatus comprising: Wherein said hardness of neutralizing member is set to 10 ° to 60 ° in Asker C measurement, the image forming apparatus according to claim 1, wherein a.